Automatic scraper for strip metal stock



May 10, 1938. F. H. NAISH AUTOMATIC SCRAPER FOR STRIP METAL STOCK" 2 Sheets-Sheet l Filed June 28, 1937 INVENTOR FREUD H NAIJH May 10, 1938. F. H. N AlsH 2,116,980

AUTOMATIC SCRAPER FOR STRIP METAL STOCK Filed June 28,Y l1957' 2 sheets-shew;

INVENTOR FRED H NAISH N UNITED STATES of the scrapers to engage the stock, will reprey sent a loss. Where it is attempted toset the Patented May 10, 1938 PATENT ori-*ica s analist i l AUToMAnc-scaAran Foa simu METAL srocx ma' awash, Birmingham. man signor u Connors ware Steel Company, a corporation of Application as, 1931, serai 16.150.141

comme." wl. so-ii i My invention `relates to an lautomatic scraper for mills rolling strip stock. l l

More particularly my invention is `applicable to mills of the class suitedv for the rolling of narrow strip stock; s'uch ashoopstock, in `which l of, 1500 feet per minute,`or 25 or more feet per second. At such speeds it `willbe obvious that whatever time interval is permitted to `elapse be-.s tween the moment that the Vmill rolls grip the` forward end of a strip of stockand the setting scraper by hand or stock actuated switch,; the

delay of a fraction `of a second,` in setting the s scraper may mean many feet of untreated stock i i the stock guides il, a stationary Ascraper frame `that must be scraped, while iffthe scraper is set in advanceof the stocks engagement be-` tween therolls, the feed of stock will bestpped,

i necessitating releaseof the scraper andcausing delay in operation and reduction oi output.

`The purpose of my present invention is-automatically to-apply the scraper cotemporaneously with the engagement of the'forward end of` the strip stock between the mill rolls. `To' this end the'scraper is set lclose as it convenientlymay be to the mill rolls on their receiving side fand electro-magnetically controlled means are employed to set the scraper to its work responsive to the increase of load coming on the mill when i it grips the stock. In other words, the increase of power required'to drive the rolls when they` take hold of the strip will act automatically and instantaneously to apply the scraper so that the unscraped waste stock on each piece rolled is `substantially limited in length to the distance between the scraper and its associated'mill pass.

It is customaryl s s s parts throughout the drawings.

Fig. lois an endview of atypical strip rolling mill showing Vmy improved automatic scraper control ,associated .with the mill power circuits laid out in a conventional diagram'.

Fig..2 is aplan viewof the` mill and scraper mechanism. s

Fig. 3 is a cross scraper elements in operative position.

Fig. 4 is a diagrammatic circuit layout for a load relay suitablelfor the control of the scraper.

.Similar reference numerals refer to similar `In the embodiment of my invention illustrated,

.I show a typical mill roll stand `comprising a housing 5, the usualbearlngs 6 andlwfor the upper and lowerrolls 8 and 9, and adjusting "guides Il receive the incoming stock and deliver it into the mill pass,.while corresponding guidesv `lilcarry the iinished stock away fromV the l rolls. s s i y i s.

I mount fast on the housing 5, adjacent to I3 comprising the spaced "scraper bars lil, I5 and I6. Asverticallymovable.scraper frame I1 carries scraper bars i8 and I9 `wlilchdepend below it and in their lowered operating position t between and coact with, bars Il, l and `I6 to i i l i A frame 20, also attached to thehousing 5, supports an upright cylinder 2l centrally' over the bar IL The movable frame I1 has end guide extensions which `slide 'in the grooves 22 formed "in the vertical sides of the frame 20. The cylinder has its pls-` ton connected centrally to the frame` i3 on its `mili side and it is adapted to be operated by coml pressed ,air supplied 4from lany suitable source, such as the tank 23 from `whence'itilows through pipe 24 toa four-way valve 25 controllingits ow to, and 4exhaust from, th'e cylinder. This `valve may be of any standard four-way type andas it` formsno particular part of4 my present H inventiomit will not be illustrated in detail.

l The valve bodyhas an exhaust outlet 26 and 'I'he valve element in the plunger 29` connected. to a lever A30 pivoted at one end to the bracket 3l and at its other end connected t o the core 32 of the solenoid 33.

As shown, fthe core passes loosely through the free end of the lever 30 and carries at-its lower i end a spring seat 34 upon which rests a coiled sectional view showing `the mill rolls the current load factor in the primary compression spring 36 that supports the lever 30. 'Ihe lever 30 is connected by a coil tension spring 36 to a bracket 31 on the valve body and thus the free end of the lever is biased downwardly against spring 35. Assuming the solenoid 33 deenergized, the parts .will occupy the position shown in Fig. 1 with the pressure admitted to the lower end of the cylinder through'fair line 31, and the upper end of the cylinder open to the exhaust through air line 28 and valve outlet 26. The scraper will be in open position and the mill rolls will be turning idle, as indicated -by the arrows, ready for the reception of the strip stock to be rolled.

The electric motor for driving the mill rolls is omitted but a metering power circuit 40, 4| therefor is shown comprising anammeter 42, a voltV meter 43, and a current load relay 44. This load relay, in the manner well understood in this art, acts to open and close a volt valve control circuit comprising the leads 45 and 46, which include the solenoid 33 and also the double safety switch 41 and the hand operated control switch 48. 'I'he load relay is of' such character that the solenoid circuit is open when the mill is idling but the moment the stock enters the pass between the mill rolls more power will be required in the primary or load responsive circuit 40, 4I and such increased flow of current will operate the load relay to close the secondary or valve control circuit 45, l46 energizing the solenoid 33, lifting the solenoid core 32 and raising the valve lever 30, against the action of spring 36, to reverse the four-way valve 25 and admit air through the line 26 into the upper end of the cylinder 22 while exhausting air from the lower end of the cylinder through the line 21 and the `valve outlet-26.' The combined action of air and gravity will thrust the movablescraper element I1 quickly downward into its operating position, shown in Fig. 3, and will hold it in this position with its scraper bars interleafed between the blades of the stationary scraper' bars so as to effectively scrape and clean the stock passing to the mill pass. As soon as the stock leaves the current will drop, causing the load relay to open the secondary or valve control circuit, whereupon the solenoid will be deenergized, and the spring 36 will reverse the four-way valve 25 to admit air below the piston in cylinder 22 and exhaust air from above the piston, so that the movable scraper blade I1 is lifted to open the scraper and allow the next stock to pass freely to the entering mill guides Il.

In Fig. 4 I have shown a conventional wiring diagram for the current load relay 44 as this may be of standard design which in various types is available on the market.

As illustrated in' Fig. 4, the primarycircuit leads 40 and 4| are respectively connected to the terminals 50 and 5| of therelay, these terminals being in turn connected to the ends of a circuit 52 which includes coils 'surrounding a plunger 53. the coils having tap leads to a connector block 54. so that the desired .tap values can be obtained for setting the plunger to operate at the desired predetermined load value. This load value is such'as will result when the mill rolls bite into the stock; and under such conditions the increased ilow of current will lift the plunger and operate the switch arm 55 to close the circuit 56, the sides of' which are connected to the terminals 51 and 58,

to which respectively the control circuit leads 45 and 46 are connected. Thus a current fiow greater than that required to drive the mill when idling will instantly lift the switch arm 55 and close the valve control secondary circuit energizing the solenoid 33 and causing the air motor, assisted by gravity, to thrust the movable scraper frame I1 into quick engagement with the stock. In like manner, the moment the mill rolls release the stock, the load factor on the primary circuit drops, the plunger 53 is'lowered, the switch 55 is opened and the secondary circuit is broken,

1 whereupon spring 36 resets the -valve to the position shown in Fig. 1 and the air pressure lifts the scraper frame I1 so that the new stock is ready to be introduced into the mill.

The switches 41 and 45 are normally closed when the apparatus is in operation and are not open as shown in Fig. 1. The switch 48, a manually controlled switch of any suitable and convenient type, is arranged so that the operator can at will open the valve controlling circuit. Thus, when the mill is starting up and the load factor willbe high, it is necessary to hold switch 46 open until the millattains idling speed, then it can be closed and the current relay 44 will thereafter automatically control it. Likewise, if anything goes wrong during the rolling operation, the strip per can be immediately disengaged from the stock by opening switch 46. Switch 41 is purely a safety switch.

While I have shown my invention in. but one form, it will be' obvious to those skilled in the art that it is not so limited, but is susceptible to various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as areimposed by the prior art or as are specliically set forth in the appended claims.

` What I claim as new and desire to secure by Letters Patent, is:

1. The combination with a mill for rolling strip stock of an automatic scraper mounted adjacent to and on the receiving side of the mill,.an electrical power circuit for the mill drive comprising a load relay, a secondary circuit controlled by said load relay responsive to the presence or absence of stock between the mill rolls, an electromagnetically controlled valve means responsive to said secondary circuit, and fluid pressure means controlled by said valve means and adapted to apply the scraper to strip stock entering the mill pass and to set the scraper for admission of fresh stock to the mill, and a load relay in the mill drive circuit adapted to control the secondary circuit and set the scraper in operating position as soon as the stock enters, and during its traverse of, the mill roll pass'.

2. 'Ihe combination with a mill for rolling strip stock, a scraper mounted close to the receiving `side of the mill and comprising cooperating stationary and movable elements, a uid pressure motor to open and close the scraper elements, a control valve for said motor, electro-magnetic means to operate said valve to reverse said motor..

an electric supply circuit for the mill drive, a

load relay responsive to the circuit flow insaid in position to render the scraper inoperative, and 75 a solenoid adapted to move the lever and valve against said spring to set the scraper in operative engagement with the stock.

4. A scraper means for a rolling mill, according to claim 2, in which the secondary circuit com prises a manually controlled switch operable to open and close the scraper elements independently of the operation of said load relay.`

5. The combination with a rolling mill having an electrical power` circuitI carrying `current for the drive of the mill rolls, a `scraper means adapted to act on the stock in its passage to the `mill and comprising separableelements operable to engage and release the stock, electro-magnetically controlled means to effect the engagement `and disengagement of said scraper elements, andv means, automatically responsive to an` abnormal current flowin the mill power circuit responsive to the engagement of stock between the mill rolls. for effecting automatically engagement of the scraper elements with the stock as soon as it is grasped by the rolling mill rolls.

6. The combination with a rolling mill having an electrical power circuit carrying current for the drive of the mill rolls, a scraper adapted to act on the stock in its passage to the mill, an electro-magnetically controlled means, automatically responsive to an abnormal current flow in the mill power circuit responsive to the engagement of stock between the mill rolls, to cause the the stock.

FRED H. NAISH. 

